New Horizons completes marathon Pluto data transfer

Artists impression of New Horizons transmitting data back to Earth(Credit: NASA/JHUAPL/SwRI)

NASA's Deep Space Network (DSN) has
received the final piece of data collected by the agency's New Horizons probe during its encounter with the dwarf planet Pluto,
which took place July 14, 2015. Data from the New Horizons mission
has revolutionized our understanding of Pluto, revealing the
planetoid to be a surprisingly dynamic and active member of our solar
system.

Unlike NASA's Dawn mission, which has
now spent over a year exploring the dwarf planet Ceres, New Horizons
never made orbit around its target.
Instead, the probe had only a brief window in which to harvest as
much information as possible, before barreling past Pluto into
the outer reaches of our solar system.

During the pass, New Horizons' meager
power supply of only 200 watts ran a sophisticated suite of seven
scientific instruments, which worked to collect over 50 gigabits of
data. This information was safely stored in two solid-state digital
recorders that form part of the probe's command and data-handling
system.

Sending this data back to Earth would
prove to be a lesson in patience. New Horizons began transmitting the
stored data in September 2015 at a rate of around seven megabits per
hour. The information was received back on Earth by NASA's Deep Space Network (DSN).

The transmission was not continuous. The natural spin of the Earth necessitated New Horizons to
transmit data in eight hour stints when the DSN was available, resulting in a transfer rate of around 173 megabits per day.

Furthermore,
the New Horizons team had to share the capabilities of the DSN with
other exploration endeavors such as the Dawn mission, further
frustrating the data transmission rate.

However, slow and steady wins the race,
and at 5:48 a.m. EDT on the 25th of October, over a year
after beginning the process, the DSN station located in Canberra, Australia, relayed the final piece of Pluto
data from New Horizons to the probe's mission operations center at
the Johns Hopkins Applied Physics Laboratory in Maryland.

The last data transmission contained
part of an observation sequence of Pluto and its large moon Charon,
as captured by the spacecraft's Ralph/LEISA imager.

"The Pluto system data that New
Horizons collected has amazed us over and over again with the beauty
and complexity of Pluto and its system of moons," comments Alan
Stern, New Horizons principal investigator from Southwest Research
Institute in Boulder, Colorado. "There's a great deal of work
ahead for us to understand the 400-plus scientific observations that
have all been sent to Earth. And that's exactly what we're going
to do –after all, who knows when the next data from a spacecraft
visiting Pluto will be sent?"